A light gas gun is a projectile launcher employing a gas having a low atomic number, specifically hydrogen or helium. The light gas is heated and pressurized in a chamber having a diaphragm behind a projectile. In response to the heating and pressurizing, the light gas ruptures the diaphragm and then is accelerated at very high velocity against the rear of the projectile to accelerate the projectile from a breech of a barrel to the barrel muzzle. Light gases are particularly advantageous for this purpose because they have very high sound speed. As the molecular weight of a gas increases, the sound speed of the gas decreases as an inverse square root function of molecular weight.
In the prior art, to enable the light gas to achieve the necessary pressure and temperature to accelerate a projectile to very high velocity, the gas is compressed by a mechanical piston driven along a "pump tube" by an electrically activated powder charge. The mechanical pistons are removed only with great difficulty from the gun barrel after a projectile is launched and the pump tube is heavy. Hence, prior art light gas guns have not been practical for field use.
It has also been suggested to provide light gas guns wherein a highly energetic electric arc is supplied to the light gas by a high voltage pulsed power supply that is connected across a metal fuse. The high voltage power supply typically has many kilojoules of energy, causing the light gas to become a strong plasma having very high temperatures that can damage a barrel wall. In addition, high energy electric power supplies have known disadvantages, curtailing the portability of light gas guns using such supplies.
It is, accordingly, an object of the present invention to provide a new and improved light gas gun and method having a reduced electric power supply.
Another object of the present invention is to provide a new and improved light gas gun and method, wherein the gun can be transported from place to place and can be used in the field.
A further object of the invention is to provide a new and improved light gas gun and method, wherein the gun is easily reused from shot to shot because it does not employ a mechanical piston and gases traversing the gun barrel are at relatively moderate temperatures that do not cause significant barrel damage.